pg.ddx.io pgsql-admin@postgresql.org mailing list archive
help / color / mirror / Atom feedNot clear with the Explain Plan output
2+ messages / 2 participants
[nested] [flat]
* Not clear with the Explain Plan output
@ 2024-05-13 15:37 Siraj G <tosiraj.g@gmail.com>
0 siblings, 1 reply; 2+ messages in thread
From: Siraj G @ 2024-05-13 15:37 UTC (permalink / raw)
To: Pgsql-admin <pgsql-admin@lists.postgresql.org>
Hello experts!
I am new in the PgSQL domain, so I need assistance in understanding the
explain plan. I took the plan of a SQL via PgAdmin and it looks like the
attached one. I am unable to see the numbers that indicate where the heavy
processing is being done, to determine the IO and cpu processing.
Is this the right way to collect explain plan? If so, how do I interpret
this? If there is another or a better way to collect this, please let me
know.
Regards
Siraj
Attachments:
[image/svg+xml] explain_plan_1715608344730.svg (124.3K, ../../CAC5iy60e7T3LUcVN94pOYxgnxvQPqrMUv-87qCUNnNoC_+gvLw@mail.gmail.com/3-explain_plan_1715608344730.svg)
download | view image
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Not clear with the Explain Plan output
@ 2024-05-13 16:16 hubert depesz lubaczewski <depesz@depesz.com>
parent: Siraj G <tosiraj.g@gmail.com>
0 siblings, 0 replies; 2+ messages in thread
From: hubert depesz lubaczewski @ 2024-05-13 16:16 UTC (permalink / raw)
To: Siraj G <tosiraj.g@gmail.com>; +Cc: Pgsql-admin <pgsql-admin@lists.postgresql.org>
On Mon, May 13, 2024 at 09:07:14PM +0530, Siraj G wrote:
> Hello experts!
>
> I am new in the PgSQL domain, so I need assistance in understanding the
> explain plan. I took the plan of a SQL via PgAdmin and it looks like the
> attached one. I am unable to see the numbers that indicate where the heavy
> processing is being done, to determine the IO and cpu processing.
>
> Is this the right way to collect explain plan? If so, how do I interpret
> this? If there is another or a better way to collect this, please let me
> know.
Just run 'explain analyze' and read the text output. Graphs, in my
opinion, hide too much info.
Normal explain looks like:
#v+
QUERY PLAN
──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
Sort (cost=35.41..35.50 rows=35 width=224) (actual time=0.160..0.162 rows=4 loops=1)
Sort Key: n.nspname, c.relname
Sort Method: quicksort Memory: 25kB
Buffers: shared hit=15
-> Hash Join (cost=1.09..34.51 rows=35 width=224) (actual time=0.046..0.153 rows=4 loops=1)
Hash Cond: (c.relnamespace = n.oid)
Buffers: shared hit=15
-> Seq Scan on pg_class c (cost=0.00..32.16 rows=70 width=77) (actual time=0.009..0.107 rows=146 loops=1)
Filter: ((relkind = ANY ('{r,p,v,m,S,f,""}'::"char"[])) AND pg_table_is_visible(oid))
Rows Removed by Filter: 280
Buffers: shared hit=14
-> Hash (cost=1.07..1.07 rows=2 width=68) (actual time=0.029..0.029 rows=2 loops=1)
Buckets: 1024 Batches: 1 Memory Usage: 9kB
Buffers: shared hit=1
-> Seq Scan on pg_namespace n (cost=0.00..1.07 rows=2 width=68) (actual time=0.013..0.015 rows=2 loops=1)
Filter: ((nspname <> 'pg_catalog'::name) AND (nspname !~ '^pg_toast'::text) AND (nspname <> 'information_schema'::name))
Rows Removed by Filter: 3
Buffers: shared hit=1
Planning:
Buffers: shared hit=9
Planning Time: 0.204 ms
Execution Time: 0.189 ms
(22 rows)
#v-
Best regards,
depesz
^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2024-05-13 16:16 UTC | newest]
Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2024-05-13 15:37 Not clear with the Explain Plan output Siraj G <tosiraj.g@gmail.com>
2024-05-13 16:16 ` hubert depesz lubaczewski <depesz@depesz.com>
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox